Comtech EF Data CDM-625, Installation And Operation Manual

Page: 263 / 322

CDM-625 Advanced Satellite Modem Revision 1
Remote Control MN-0000036 (Ref MN/CDM625.IOM)
D.5 Packet Structure
Controller-to-Target:
Start of
Packet Target
Address Address
De-limiter Instruction
Code Code
Qualifier Optional
Arguments End of
Packet
<
ASCII code 60
(1 character) (4 characters)
/
ASCII code 47
(1 character) (3 characters)
= or ?
ASCII codes
61 or 63
(1 character) (n characters)
Carriage Return
ASCII code 13
(1 character)
Example:
<0000/RSH=30[cr]
Target-to-Controller:
Start of
Packet Target
Address Address
De-limiter Instruction
Code Code
Qualifier Optional
Arguments End of
Packet
>
ASCII code 62
(1 character) (4 characters)
/
ASCII code 47
(1 character) (3 characters)
=, ?, !, or *
ASCII codes
61,63,33 or 42
(1 character)
(From 0 to n
characters)
Carriage Return,
Line Feed
ASCII codes
13,10
(2 characters)
Example:
>0000/BBU=107[cr][lf]
D.5.1 Start of Packet
Controller to Target:
This is the character '
<
' (ASCII code 60)
Target to Controller:
This is the character '
>
' (ASCII code 62)
Because this is used to provide a reliable indication of the start of packet, these two characters
may not appear anywhere else within the body of the message.
D.5.2 Address
Up to 9,999 devices can be uniquely addressed. In EIA-232 applications this value is set to 0. In
EIA-485 applications, the permissible range of values is 1 to 9999. It is programmed into a target
unit using the front panel keypad.
Important note:
The controller sends a packet with the address of a target - the destination of the
packet. When the target responds, the address used is the same address, to indicate to the
controller the source of the packet. The controller does not have its own address.
D–3